Among the goals of this project are to describe age differences and changes in reasoning performance and to investigate psychological processes underlying such age-related performance. This year, concept problem solving was one of many measures included in analyses relating cognitive performance to glucose tolerance in the women in the Baltimore Longitudinal Study of Aging (BLSA). When age, education, and obesity were taken into account, only concept problem solving was related to the concentration of glucose in the blood two hours after ingestion of a glucose load. Although this result was statistically significant, the magnitude of the effect was very small. Furthermore, diabetic (noninsulin dependent) men in the BLSA, were not different from matched controls in concept problem solving. Given this and the negative findings with many other cognitive measures in women, the relationship between glucose performance and complex reasoning clearly needs further study; and this will be investigated further in the BLSA.